10 Yr Transformation of the Obscuring Wind in NGC 5548

A decade ago the archetypal Seyfert-1 galaxy NGC 5548 was discovered to have undergone major spectral changes. The soft X-ray flux had dropped by a factor of 30 while new broad and blueshifted UV absorption lines appeared. This explained emergence obscuring wind from accretion disk. Here we report on striking long-term variability disk in including observations taken 2021-2022 with Swift Observatory Hubble Space Telescope's (HST) Cosmic Origins Spectrograph (COS). hardening as result obscuration has declined over years, reaching its lowest 2022 at which point find C IV line be nearly vanished. associated narrow low-ionization lines, produced previously when shielded X-rays, are also remarkably diminished 2022. We highly significant correlation between variabilities equivalent width line, demonstrating that is inherently linked winds. derive for first time relation covering fractions using evolution. likely caused an increasingly intermittent supply outflowing streams results growing gaps interstices clumpy wind, thereby reducing fractions.